Pump



Aug. 15, 1967 R. A. THON 3,335,668

PUMP

Filed Feb. 1, 1966 2 Sheets-Sheet 1 IIIIIIIIII'I'I'IIIA Inventor RONALDA THON Marne? United States Patent Ofifice Patented Aug. 15, 19673,335,668 PUMP Ronald A. Thon, Arlington Heights, 11]., assignor toMolon Motor 8: Coil Crp., Rolling Meadows, Ill., a corporation ofIllinois Filed Feb. 1, 1966, Ser. No. 524,113 6 Claims. (Cl. 103-403)This invention relates to centrifugal pumps and the constructionthereof.

In numerous applications, such as liquid electrostatic duplicatingmachines, humidifiers, advertising displays, office machines andphotographic developing machines, a relatively small centrifugal pump oflow cost and relatively reliable performance could be used to advantage,especially if so constructed as to be readily adapted to differentenvvironments represented by such diverse applications. Cost factorsreduced by the present invention relate to the elimination of scaledbearings and/ or shaft seals, the manner of protecting an electric motorfrom the fluid being pumped, and the elimination of fasteners such asscrews and rivets. Other important factors contributing to the cost of apump are the number of components comprising the pump, and the laboremployed in assembling the components to complete the pump. Accordingly,the primary object of the present invention is to produce a reliable,low cost, centrifugal pump characterized by molded plastic parts, few innumber, and readily assembled without the necessity of fasteners.

A more specific object of the invention is to construct a low costcentrifugal pump with molded plastic components characterized by acolumn or tube having one end adapted to be press fitted on a motorsupport and with the other end thereof formed to include a bearing foran impeller shaft; a one piece impeller being adapted to be secured tosaid shaft, and a pump housing or cover being adapted to be snap-fittedto said column and immersed in a fluid.

The pump of the present invention is adapted to be related to a motorfor disposition above a liquid. The impeller shaft is connected at oneend to the motor rotor, and another object of the present invention isto support the rotor by the same bearings which support the impellershaft.

Another object of the invention is a low cost pump having a moldedplastic column which extends from a motor support to an impellerhousing, said column being easily dimensioned to fit the many differentenviron ments where the pump may be employed, and having an integrallyformed bearing for an impeller drive shaft and a separate, snap-fittedimpeller cover which may be modified for directing flow of a liquid.

Other specific objects of the invention are to provide flexibility inpumps by having a molded attaching column which can be cut to variouslengths and by having a pump housing which can be readily assembled andported in alternative fashions.

Other and further objects of the present invention will be apparent fromthe following description and claims and are illustrated in theaccompanying drawings Which, by way of illustration, show preferredembodiments of the preesnt invention and the principles thereof and whatis now considered to be the best mode contemplated for applying theseprinciples. Other embodiments of the invention embodying the same orequivalent principles may be used and structural changes may be made asdesired by those skilled in the art without departing from the presentinvention.

In the drawings:

FIG. 1 is an elevational view of a pump constructed in accordance withthe preferred embodiment of the invention;

FIG. 2 is a perspective view of the distal end of the pump with the pumpcover removed;

FIG. 3 is a partial sectional view of the pump construction of FIG. 1;

FIG. 4 is a view taken along the lines 4-4 of FIG. 3, in the directionof the arrows and showing the pump cover;

FIG. 5 is an enlarged fragmentary sectional view of the distal end ofthe pump;

FIG. 6 is a fragmentary sectional view of the pump cover;

FIGS. 7, 8 and 9 are illustrations of an alternative porting of the pumphousing;

FIG. 7A is a fragmentary view illustrating a nozzle; and

FIG. 10 is an enlarged sectional view at the base plate of the motor.

Referring now to the drawings and more particularly to FIGS. 1 and 3,there is illustrated a centrifugal pump 10 constructed in accordancewith the preferred embodiment of the invention. In its preferred form,the pump 10 includes a motor assembly 12, a motor support base 13, acolumn 14, a rotatable impeller 15 and a pump housing defined in part bya separable cover 16. As best seen in FIG. 3, the motor assembly 12drives a drive shaft 18 which is disposed internally of and coaxiallywith the hollow column 14, the lower end of the drive shaft 18 beingfixed to the impeller 15 to rotate the impeller 15 within the pumphousing. The cover 16 of the pump housing is of a convolution shapehaving a central inlet port 20 through which fluid enters for movementby the impeller 15 to an outlet port 21.

The present invention is characterized by its low cost of manufacturedue to relatively few, inexpensive, and uncomplicated parts, and itsreadily assembled nature without the requirement for the usual screw orrivet type fasteners. In accomplishing the low cost production, it ispreferred that the column 14 be a molded plastic one piece element ofDelrin, nylon or like plastic and including a wall or center plate 25,FIG. 5, formed with a central aperture 26. The aperture 26 is enlargedto enable the shaft 18 to be easily extended therethrough and supportedby a bearing 26B that is part of the center plate 25 at the distal endof the tube 14. Shaft 18 extends through a hollow boss 28, FIG. 3, whichis part of the motor support base 13.

Thus, the boss 28 is preferably an integral portion of a generallyrectangular base plate 30, serving .as a motor support, and which ispreferably formed from a die cast part which affords the entire base 13.A pair of projecting spacers 31 extend from the plate 30, FIG. 3, toreceive threaded studs 32 to fasten the stator portion 34 of the motormeans 12 to the support plate 30. A central rotor 35, FIGS. 3 and 10, iscoaxial with the drive shaft 18 and is secured thereto for rotating theshaft 18 and attached impeller 5. It will also be observed that shaft 18is coaxial within the sleeve or tube 14. Referring now to FIG. 10, therotor 35 is engageable with a spacer 36E resting on a porous bronzeself-centering bearing 36 which in turn is supported on the conical seatof a boss 37.

The boss 37 is formed within the base 13 of which the support 30 is anintegral part of an entire die casting. An annular wall 38 surrounds andis spaced from the boss 37, the space between being packed withoil-impregnated felt rings 40A and 4013. The bearing is resilientlyretained by a spring 41, and the spring in turn is retained by a washer43. The free end of the wall 38 is swedged at 388 to confine the partsdescribed above as located within the base 13;.

The bearing 36 thus holds the rotor 35 against axial thrust while alsoserving as a rotary bearing support for the rotor and shaft 18.

To facilitate the assembly of the pump, the internal bore in the upperportion 14A, FIG. 1, of the column is configured to have a tight pressfit with the outer peripheral surface 28A, FIG. 10, of the boss 28. Inits preferred construction, the cover 16 of the pump housing issnapfitted to the opposite or distal end of the column 14 thereby againeliminating the need for screw type fasteners, as will be explained inmore detail below. Alternatively, the pump housing cover 16 could bepress-fitted on the end of column 14, but this makes more difficult theremoval of the housing 16 from the column 14 for servicing.

As can best be understood from FIG. 2, the pump housing cover 16 isprovided with peripheral ledges or flanges 40 extending at right anglesbeyond a base or shoulder portion 41. The flange 40 is provided with aseries of spaced lugs or projections 42 extending radially toward theinterior of the cover 16. The distal end of the column 14 is formed witha flat attaching plate or portion 44, FIGS. 2 and 5. The peripheral edge45 of the plate 44 is configured to snap fit within the confines of theflange 4G with the fiat bottom surface 46 of the column plate 44 fittedflush against the right-angled shoulder 41 of cover housing 16. Thisararngement produces an acceptable seal between the cover 16 and thetube 14, and since no separate metal fasteners are used to connect thetube to the motor support or to the cover 16, there are no metal partsthat can become corroded.

In an assembly operation, the housing 16 is snap-fitted onto theattaching plate 44 of the column 14 by forcing the lugs 42 over theperipheral edge 45 of the base 44, thereby locking the housing 16against accidental removal. During the snap fitting operation, the lugs42 flex the flange 40 to permit the peripheral edge 45 of the plate 44to move therepast whereupon the flange 40 returns the lugs 42 to overliea portion of the peripheral edge 45 of the base plate 44 on the column14 as shown in FIG. 5.

As can best be understood from FIG. 5, it is preferred that the outletport 21 be formed in a boss integral with the attaching plate 44, FIG.5, and having a hollow bore 51 through which fluid may exit the pumpPreferably, the outer peripheral surface of the outlet port 21 istapered so as to easily fit a discharge conduit C, FIG. 1, connected tothe pump 10.

As the fluid enters the pump housing 16 through the central aperture 29in the cover 16, the revolving impeller blades 54 of the impeller forcethe fluid in a path defined by a convolute internal wall 55, FIG. 2,within the cover 16 and toward an outlet cavity 56 therein which isdisposed directly opposite the outlet bore 51, FIG. 2. Thus, the fluidenters the inlet port at the center of the housing cover 16 and is movedby the impeller 15 through the bore 51 to exit the pump. Alternatively,the pump housing 16 may include either a single or double outlet byforming openings in one or both of a pair of bosses 60 and 61, FIGS. 2and 4, which are integral with the member 16. Thus, as can be seen inFIGS. '7, 8 and 9, the respective bosses 60 and 61 may be apertured asat 62 and 63 to provide either a single or double outlet for the fluidbeing pumped. A nozzle as N, FIG. 7A, having a knurled outer surface,can be easily pressed into such a port to receive a conduit. Manifestly,the bore 51 of the outlet 21 may be plugged when an outlet is providedthrough a boss 66 or 61.

Adaptation of the pump to a particular use may be easily accomplished byappropriately dimensioning the length of the tube 14. The tube can beturned on boss 28 to port from the outlet in any desired direction.

Preferably, the impeller 15 is an integral one piece element molded of aplastic such as Delrin, nylon or the like having an integral andseparate hub portion 68, FIG. 5, through which extends an end 69 of thedrive shaft 18. The impeller hub is press-fitted to the end 69 of the 4shaft 18 which extends beyond the bearing 26B toward the cover 16. Theintegrally molded vanes 54 project outwardly from an integral circularplate 72 disposed adjacent an annular surface 65 on the underside of thebase 44 of the column 14.

As seen in FIG. 5, the impeller 15 is free to rotate intermediate theend wall 56 of the pump housing 16 and the interior surface 65 of theattaching base 44 of the column 14. Advantageously, the rotor 35 issupported by the same bearings 36 and 26B which support shaft 13 forrotation, thereby minimizing the number of parts.

To avoid liquid rising in the tube 14 to the motor assembly, a suitablevent opening 75, FIG. 1, is provided in the tubular column 14 inconjunction with a groove 28G and communicating notch 28N formed in theboss 28.

In its preferred commercial form, the motor 12 is a horsepower motor,capable of delivering one gallon per minute at a 24 inch head ofpressure. However, the present invention is not to be construed aslimited to these dimensions and operating characteristics inasmuch asthe principles of the present invention are applicable to other sizes ofpumps. Also, the configurations and proportions of the enclosure for theimpeller afforded by the cover 16 and the column end plate 44 may bevaried from that described in the illustrated embodiment of theinvention.

For servicing a pump constructed in accordance with the preferredembodiment of the invention, the pump housing cover 16 may be readilyremoved by applying a force to pull the pump housing cover to releasethe snap fit of the cover relative to the column 14.

It will be seen from the foregoing that the present pump embodies agreat deal of flexibility in adaptation to various uses, due principallyto the use of the column 14, easily dimensioned, and which is itself atone end press-fitted to a boss as 28 on the motor support. In turn, thepump housing or cover 16 is snap fitted to the opposite end of the tube14, to encase the impeller, and to this extent separate fasteners areeliminated. Resultantly, this assembly can be easily rotated on thesupport 28 to direct the outlet port of the pump in any desireddirection. A relatively inexpensive but nevertheless reliable seal iseffected between the cover and the periphery of the end plate 44 of thetube 14, and the motor is safeguarded against contamination of liquidbeing pumped by venting the interior of the tube 14 in the mannerdescribed. The rotor is supported by the bearing means 36 and 263 whichsupport the impeller shaft 18, characterized in one regard by thecoaxial relationship between the tube 14, shaft 18 and the axis of therotor.

Hence, while I have illustrated and described preferred embodiments ofmy invention, it is to be understood that these are capable of variationand modification.

I claim:

1. In a submersible centrifugal pump adapted to be driven by the rotorof a non-submersible motor: a motor support means having a bossprojecting therefrom, a tube press fitted at one end on said boss andhaving an attaching plate affording part of a pump housing at the otherend, a pump housing cover snap fitted to said attaching plate andconfigured to afford a pump housing therewith, an impeller shaftextending to said pump housing, and an impeller secured to said shaftwithin the pump housing.

2. A pump according to claim 1 wherein the impeller shaft is coaxiallyarranged within said tube, said attaching plate being formed with abearing supporting said shaft, said motor support means having anotherbearing for said shaft, and a rotor secured to said impeller shaft andcoaxial therewith whereby the rotor and shaft are both supported by thesame bearings.

3. A pump according to claim 1 wherein said cover includes lugs having asnap-fit relation to an edge of said attaching plate, and wherein theattaching plate and cover have engaged peripheral surfaces affording apump housing seal without the need for interposing a separate seal.

4. In a submersible centrifugal pump adapted to be driven by the rotorof a non-submersible motor: a motor support means having a bossprojecting from one side thereof and supporting a bearing, a plastictube pressfitted at one end on said boss and having at the other end anintegral attaching plate affording part of a pump housing, a separableplastic cover snap-fitted to the other end of said tube to complete thepump housing, said attaching plate also being formed with a bearing, animpeller shaft coaxial within said tube and supported for rotation insaid bearings, a rotor on the other side of said motor support means andbeing secured to one end of said impeller shaft, a plastic impellerafiixed to the other end of said impeller shaft and being located withinsaid pump housing, vent means for venting the interior of said tube, andsaid pump housing being formed with inlet and outlet ports for the fluidto be pumped.

5. A pump according to claim 4 wherein said cover includes lugs having asnap-fit relation to an edge of said attaching plate, and wherein theattaching plate and cover have engaged peripheral surfaces affording apump housing seal without the need for interposing a separate seal.

6. A pump according to claim 5 wherein said cover is formed with a pairof bosses which can be alternatively selected for the outlet port.

References Cited UNITED STATES PATENTS ROBERT M. WALKER, PrimaryExaminer. HENRY F. RADUAZO, Examiner.

1. IN A SUBMERSIBLE CENTRIFUGAL PUMP ADAPTED TO BE DRIVEN BY THE ROTOROF A NON-SUBMERSIBLE MOTOR: A MOTOR SUPPORT MEANS HAVING A BOSSPROJECTING THEREFROM, A TUBE PRESS FITTED AT ONE END ON SAID BOSS ANDHAVING AN ATTACHING PLATE AFFORDING PART OF A PUMP HOUSING AT THE OTHEREND, A PUMP HOUSING COVER SNAP FITTED TO SAID ATTACHING PLATE ANDCONFIGURED TO AFFORD A PUMP HOUSING THEREWITH, AN IMPELLER SHAFTEXTENDING TO SAID PUMP HOUSING, AND AN IMPLELLER SECURED TO SAID SHAFTWITHIN THE PUMP HOUSING.